Genetic predisposition to the presence and 5-year clinical progression of hip osteoarthritis.
Pollard TCB., Batra RN., Judge A., Watkins B., McNally EG., Gill HS., Arden NK., Carr AJ.
Genetic factors are important in the aetiology of hip osteoarthritis (OA), but studies are limited by cross-sectional design and poor association with clinically important disease. Identifying cohorts with progressive OA will facilitate development of OA biomarkers. Using a middle-aged cohort with genetic predisposition to hip OA and a control group, we compared the prevalence of clinical and radiographic hip OA and incidence of progression over 5 years.123 individuals (mean age 52 years) with a family history of total hip arthroplasty (THA) ('sibkids') were compared with 80 (mean age 54 years) controls. The prevalence of radiographic OA [scored according to Kellgren & Lawrence (K&L)], clinical features, and incidence of clinical progression over a 5-year period were compared. A multivariate logistic regression model was used to adjust for confounders.Sibkids had odds ratios (ORs) of 2.7 [95% confidence interval (CI) 1.1-6.3, P = 0.02] for hip OA (K&L grade ≥2), 3.4 (1.4-8.4, P = 0.008) for clinical signs, and 2.1 (0.8-5.8, P = 0.14) for signs and symptoms. Over 5 years, sibkids had ORs of 4.7 (1.7-13.2, P = 0.003) for the development of signs, and 3.2 (1.0-10.3, P = 0.047) for the development of signs and symptoms.Compared to a control group and after adjustment for confounders, individuals with genetic predisposition to end-stage hip OA have higher prevalence of OA, clinical features, and progression. In addition to structural degeneration, the inherited risk may include predisposition to pain. Genetically-loaded cohorts are useful to develop hip OA biomarkers, as they develop progressive disease at a young age.